Question

The phase difference between the particles a and b for a wave located

Answer 1

The phase difference between a node and its nearest antinode is π2π2 or 90 degrees. This can be seen by thinking of the wave as a simple sine function. There is a node at 0, then again at ππ, before the whole thing begins to repeat at 2π2π. The antinodes are half way between each pair of adjacent nodes, at π2π2, 3π23π2, etc.